I. Field of the Invention
The present invention relates to communication systems. More particularly, the present invention relates to a novel and improved method for providing rate and service negotiation in a wireless communication system.
II. Description of the Related Art
The use of code division multiple access (CDMA) modulation techniques is one of several techniques for facilitating communications in which a large number of system users are present. Other multiple access communication system techniques, such as time division multiple access (TDMA), frequency division multiple access (FDMA), and AM modulation schemes such as amplitude companded single sideband (ACSSB), are known in the art. However the spread spectrum modulation technique of CDMA has significant advantages over these modulation techniques for multiple access communication systems. The use of CDMA techniques in a multiple access communication system is disclosed in U.S. Pat. No. 4,901,307, issued Feb. 13, 1990, entitled xe2x80x9cSPREAD SPECTRUM MULTIPLE ACCESS COMMUNICATION SYSTEM USING SATELLITE OR TERRESTRIAL REPEATERSxe2x80x9d, assigned to the assignee of the present invention, of which the disclosure thereof is incorporated by reference herein.
A method for transmission of speech in digital communication systems that offers particular advantages in increasing capacity while maintaining high quality of perceived speech is by the use of variable rate speech encoding. The method and apparatus of a particularly useful variable rate speech encoder is described in detail in U.S. Pat. No. 5,414,796, assigned to the assignee of the present invention, of which the disclosure thereof is incorporated by reference herein.
A variable rate speech encoder provides speech data at full rate when the talker is actively speaking, thus using the full capacity of the transmission frames. When a variable rate speech coder provides speech data at a less than maximum rate, there is excess capacity in the transmission frames. A method for transmitting additional data in transmission frames of a fixed predetermined size, wherein the source of the data for the data frames provides the data at a variable rate is described in detail in U.S. Pat. No. 5,504,773, assigned to the assignee of the present invention, of which the disclosure thereof is incorporated by reference herein. In the above mentioned patent, a method and apparatus is disclosed for combining data of differing types from different sources in a data frame for transmission.
As digital communication systems become more prevalent, applications of the systems are growing. As the availability of the applications grow, there is an increasing probability of differing capabilities between devices on each end of a communication link. Such differing capabilities can be in the form of encoding or decoding frame structure formats, or in service types provided or in data rates supported. As the probability of differing capabilities grows there is an increasing need for service negotiation between devices attempting to communicate in a wireless communication system.
The present invention is a novel and improved method for performing rate and service negotiation in a digital communication system. In the exemplary environment of a wireless communication system, service negotiation is described between a mobile station and a base station. In the exemplary embodiment, the mobile station and base station communicate data in frames. The data communicated may be primary or speech data, secondary or digital data, or signaling data.
It is an object of the present invention to provide a method and apparatus for service negotiation in a wireless communication system. One possible case when service negotiation might be used includes determining initial type of service when a traffic channel connection is first originated. Another case when service negotiation might be used is in modifying the existing service type while maintaining the traffic channel connection. A third case when service negotiation may be used is dropping the existing service and adding a new service while maintaining the traffic channel connection (e.g., changing from transmitting speech to transmitting modem or facsimile data). A fourth case when service negotiation might be used is in adding a new service while maintaining the traffic channel connection. For example if one is transmitting speech data and then wishes to transmit modem data in parallel. A fifth case where service negotiation may be used is in modifying existing service due to changes in the link such as range between the mobile station and base station (e.g. decreasing transmission rates as range increases and increasing transmission rates as range decreases) or during handoff between base stations where different speech coders or different rate sets may be used.
It is an advantage of the present invention to provide a method and apparatus for performing the service negotiation process with minimum data transfer over common channels, i.e. paging channels or access channels, and if the service configuration is not accomplished over the common channels to continue service negotiation over traffic channels of additional capacity.
In an alternative embodiment, no information about the traffic channel connection would be specified in the origination message with all negotiation taking place over the traffic channel. All that is specified on the access channel is the desire to make the traffic channel connection and service negotiation would be deferred to the traffic channel communications. This type of service negotiation is particularly useful in mobile to satellite communications, but is applicable to all communication systems.
It is further an advantage of the present invention to provide a method and apparatus for changing the service configuration between communicating devices without dropping the traffic channel connection currently in place. Such cases where changing the service configuration without dropping the traffic channel connection is desirable include providing an additional service or completion of a service in a multiple service traffic channel connection and a change in rate compatibility or desirability due to a change in communication environment or logistics. In the present invention, in a wireless communication system in which a first communication device originates a communication service with a second communication device, a method for negotiating service configuration is disclosed, comprising the steps of generating a request message indicative of a service configuration at the first communication device, transmitting the request message, receiving the transmitted message at the second communication device, determining if the service configuration request is acceptable to the second communication device in accordance with the current capabilities of the second communication device, generating a response message in accordance with the determination, and transmitting the response message.
Also, in the present invention an apparatus for transmitting information is disclosed comprising a service negotiator for providing a message indicative of a requested service configuration, and a transmitter for transmitting the service request message. Further disclosed in the present invention is a system for receiving information comprising a receiver for receiving a transmitted message indicative of a requested service configuration, and a service negotiator for determining in accordance with a predetermined set of parameters a response message to the request message.
In addition, a method is disclosed for changing service configuration of a traffic channel connection without terminating the traffic channel connection. In an exemplary embodiment of a wireless communication system in which a first communication device is communicating with a second communication device and wherein the first communication device requests a change of service configuration without terminating the current traffic channel connection, a method for negotiating a change in service configuration, comprises the steps of generating a request message indicative of a request to change service configuration at the first communication device, transmitting the request message concurrently with transmitting data in the current service configuration, receiving the transmitted message at the second communication message at the second communication device, determining if the service configuration request is acceptable to the second communication device in accordance with the current capabilities of the second communication device, generating a response message in accordance with the determination, and transmitting the response message.
Though the present invention is illustrated in the exemplary embodiment in a wireless communication system, it is equally applicable to any communication system where communication resources may be negotiated. It is envisioned that the present invention is equally applicable to wireline communication systems where physical layer capabilities may be negotiated, and in fixed satellite communication systems. In addition, the present invention applies equally to cases of one way communication from the base station to the mobile station, only or from the mobile station to the base station only.